| 摘要 |
PURPOSE: An apparatus for preventing lightning in a telephone line is provided to prevent the communication equipment from damages to the communication equipment due to surge voltage caused by the lightning flowed from the telephone line. CONSTITUTION: A telephone line lightning prevention apparatus(200) configured between a communication equipment(100) and a switchboard(300) is composed of a first matching part(210), a second matching part(250), a DTMF(Dual Tone Multi Frequency) detection part(220), a control part(230), a switching part(240), and a ring detection part(260). The first and second matching parts(210,250) connected with the communication equipment(100) and the telephone line forms pseudo communication loops selectively. The DTMF detection part(220) detects and outputs DTMF signals supplied through the telephone line from the communication equipment(100). The control part(230) forms and controls the communication loop in the communication equipment(100) and the switchboard(300). The ring detection part(260) detects a ring detection signal and supplies it to the control part(230).
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